1. Field of the Invention
This invention relates to a wide-screened multiscreen display made by heaping a plurality of unit displays (called also, cube projection displays) in vertical and horizontal directions and a process for assembling the same. Through this display and process the operations of conveying and stacking the cabinets of respective unit displays and the operations of the adjustment and maintenance after stacking the cabinets may be efficient, the space efficiency in conveying and storing the cabinets may be improved, and the width of the boundary (joint width) between the screens of the respective unit displays may be made small.
2. Description of the Related Arts
Conventional multiscreen displays are of a front surface projecting type, and a back surface projecting type. In the front surface projecting type displays, an image light from a projecting unit is projected from the front surface of the screen. In the back surface projecting type displays, an image light is projected from the back surface of the screen. The back surface type multiscreen display which is low in the influence of the surrounding light is generally prevalent. In such back surface type multiscreen display, he screen is divided vertically and horizontally to define a plurality of zones so that image lights from a plurality of projecting units may be projected onto the respective plurality of zones. As such, one image may be displayed on multiply zones, or one image may be displayed as divided into a plurality of images that are displayed respectively on the plural zones.
The conventional multiscreen display can be formed to obtain a large picture screen by arranging a plurality of (9 in the drawing) unit displays 1 in the vertical and horizontal directions, as shown in FIG. 53.
FIG. 54 shows an appearance view of an example of the unit display. FIG. 55 shows a vertically sectioned view of the same.
As shown in these figures, the unit display 1 has a screen fitting frame 4 arranged on the front surface of a cabinet 2. The unit display is formed by containing within the cabinet 2 a screen 3 and light box parts consisting of optical system parts 5 for projecting an image light onto the back surface of the screen 3 and a chassis part 6. Connecting metal fixtures 7 and 8 are fitted on the upper and lower surfaces of the outside of the cabinet 2 for fixing the respective upper and lower unit displays 1 with each other when a plurality of unit displays 1 are stacked up in multiple steps. The above mentioned screen 3 is formed of a Fresnel lens 3B on the inner surface side and a lenticular lens 3A on the front surface side.
FIG. 56 shows an example of the above mentioned unit displays as stacked up in steps. The upper and lower unit displays 1 are connected with each other through bolts 9 by connecting metal fixtures 7 and 8 arranged above and below the respective cabinets.
When connecting the unit displays in a vertically stacked manner as discussed above, the entire cabinet will have to be lifted and connected above and below while being fitted in the fixed position, creating danger due to the heavy labor involved. Also, during this connection and positioning the heavy object may have to be slid in small increments toward the front, rear, right and left to obtain a precise fit, taking a long time.
Further, when multiple unit displays are stacked in the vertical direction, weight of the units will reduce the size of the gap between them. But due to the weight of those units, a gap between the units will likely be produced in the horizontal direction as is shown in FIG. 57 by gap A.
Even when the outer peripheral angles 10 and 11 are combined via a bolt (indicated by the arrow) from outside, it is difficult to perfectly eliminate the gap A in such an arrangement.
The above-described problem will occur when the weight of the unit display 1 is heavy, its contour is large and the unit display 1 is connected or fastened from outside the cabinet. As a result, the quality of the multi-picture will be deteriorated.
Further, when the unit displays are incrementally stacked in steps, it is necessary to use a machine such as a crane. Use of such a machine requires that the internal space of the installing place is wide.
Also, the depth and contour of the cabinet is large, and the conveying efficiency is low. As a multi-picture is made, many unit displays as 4, 9 or 16 units will be conveyed at once. Therefore, when a multi-picture display is made, the volume of each unit display must be reduced to elevate the conveying efficiency. (There will be a case that they can not be conveyed at once.)
Operations such as adjusting the chassis and optical system that are performed after the units are stacked, and the operations such as replacing deteriorated internal parts during service are all made from the back surface side.
When the cabinet is used with a multi-picture for a long time, dust will be often deposited on the front surface and back surface of the screen. It is difficult and convenient to wipe off this dust when the cabinet is deep as it has been in the past. That is, if the light box part is intended to be pulled out and wiped, it will be difficult and inconvenient for the hand to reach the part.
As discussed above, the assembling operation required for incrementally stacking unit displays when making a multi-screen type displays is dangerous and complicated, a wide space is required for the installing place, and it is difficult to get the installing precision. Further, because the contour of each unit used to make the display is so large, the conveying efficiency is low and it is inconvenient to perform service or the like on the units.
FIG. 58 shows a formation of another example of the unit display 1. FIG. 59 shows a partly sectioned view in line 59--59 in FIG. 58.
In each unit display 1, as shown in FIG. 58, a rear projector 12 is arranged within a cabinet 2, the peripheral edge of a screen 3 is pressed with a screen fitting frame 4 on the front side of the cabinet 2, and the periphery of the screen 3 is pressed with an L-shaped metal fixture 13. The screen fitting frame 4 is secured so as to be integral with the cabinet 2.
As shown in FIG. 59, the screen 3 is a Fresnel lens 3B on the back surface and a lenticular lens 3A on the front surface so that lights may be once collected by the Fresnel lens 3B and then divided on the right and left by the lenticular lens. When the screen 3 is dropped into the screen fitting frame 4 and is pressed against and fixed to the front end part (receiving part) of the cabinet 2 with the L-shaped metal fixture 13, the screen 3 will be fitted. Then, the L-shaped metal fixture 13 will be fixed to the screen fitting frame 4 with screws 14 so that the screen 3 may not be removed.
Now, the above mentioned screen 3 fixing method has the following defects (1) to (3):
(1) As the screws 14 are used to fit the L-shaped metal fixture 13 to the screen fitting frame 4, the thickness L1 of the screen fitting frame 4 will require the thickness of the screw part. PA1 (2) Also, because the L-shaped metal fixture 13 holds the screen 3 only on the outer periphery, when the screen fitting frame 4 is instantaneously transformed to be diamond-shaped by an external force (particularly in the diagonal direction) during conveyance or handling, the screen 3 will be likely to be disengaged out of the L-shaped metal fixture 13. Particularly, because the lenticular lens 3A is thinner than the Fresnel lens 3B, that the lenticular lens 3A part will likely be disengaged out of the L-shaped metal fixture. Therefore, the dimension L2 of the L-shaped metal fixture 13 must be at least wider than the dimension L3 of the screen receiving part of the cabinet 2. In order that the screen 3 may not be disengaged out of the screen fitting frame 4, the dimension L2 of the L-shaped metal fixture 13 must be increased and, at the same time, the dimension L3 on the cabinet 2 side must also be increased to be as large as L2. Further, the transformation of the central part of the screen 3 is provided with no inhibiting force and is left free. For example, even if the L-shaped metal fixture 13 is replaced with a smaller one after the display has been installed in a set place, the dimension L3 on the cabinet 2 side and the dimension L1 on the screen fitting frame 4 side will still remain large and, as a result, when the unit displays are incrementally stacked in steps, the effective picture will be small. PA1 (3) In addition, in the multiscreen display, in order to elevate the quality of the entire picture, the linearity of the convergence must be adjusted between the respective unit displays 1. However, there is nor criterion in such adjustment. PA1 (1) A multiscreen that is formed of the lenticular lens 16A, Fresnel lens 16C and shielding plate 16D, is complicated and expensive. PA1 (2) The Fresnel lens 16B is only inserted, is poor in the environmental stability, slips and deflects. (Therefore, as another countermeasure, a part of the Fresnel lens 16B is nailed to the transparent plate 16C with fine nails so as to be reinforced. However, a deflection (such as an environment variation difference by the plate thickness difference) will occur between the Fresnel lens 16B causing transparent plate 16 and the picture quality will reduced. PA1 (3) Further, because the screen part and the rear projector 12 are separately assembled (installed) on the spot (in the setting place), it will be difficult to precisely align all optical axes when multidisplayed. PA1 a first cabinet containing the above mentioned screen parts; PA1 a second cabinet containing the above mentioned light box parts, set so that the contour dimension may be smaller than the inside dimension of the above mentioned first cabinet and movable and containable inside the above mentioned first cabinet; PA1 a plurality of shafts movable forward and rearward with respect to the above mentioned first cabinet; PA1 a means provided at one end of said shaft to regulate the rearward movement; PA1 a fixing means for passing and fixing the other end of the above mentioned shaft to the above mentioned second cabinet; PA1 a guide means removably secured in the rear end part to the rear end of the above mentioned second cabinet, guiding the movement of the above mentioned shaft and of a fixed length shorter than the length of the above mentioned shaft, for fixing in a fixed position the above mentioned second cabinet with respect to the above mentioned first cabinet; and PA1 a securing means for removably securing the rear end part of this guide means to the rear end of the above mentioned second cabinet.
From the above, the dimension L4 of the peripheral edge of the screen 3 will become very large and, when the unit displays 1 are incrementally stacked in several steps as in FIG. 53 to be of a multiscreen type, the width M of the joint by the combination will become large, the information amount of the picture will become small and, at the same time, the picture will become distorted.
FIG. 60 is a perspective view of another conventional example of the multiscreen display. FIG. 61 is a sectioned view on line 61--61 of FIG. 60.
In FIG. 60, a screen 16 is arranged on the front surface of a cabinet 15 and a plurality (four in the drawing) of rear projectors 12 are arranged within the cabinet 15. In this formation, as a method of eliminating the joint of the lenticular lenses, the rear projector 12 and screen 16 are separately made, only the screen 16 part is made a jointless formation of the lenticular lens and the plurality of rear projectors 12 are separately combined into a turret so that the optical axes of the Fresnel lenses of the screen may be aligned to be a multiscreen.
More specifically, with reference to FIG. 61, a plurality (four in the drawing) of the Fresnel lenses 16B corresponding to the respective rear projectors 12 are arranged in the rear of the lenticular lens 16, and are further lined with a thick strong transparent plate 16C (for example, an acrylic plate) (to function as a supporting plate) in the rear. The thick transparent plate 16C and a shielding plate 16D are jointed and fastened to be integral by inserting the thin shielding plate 16D between the end surfaces of the respective thick transparent plates 16C. The four Fresnel lenses 16B are held between lenticular lens 16A and this integral transparent plate 16C to form an integral screen of a multipicture. Then, the plurality of rear projectors 12 are arranged as combined in a turret by a separate body 17 so that the optical axes of the respective Fresnel lenses 16B may be aligned to make a multiscreen.
However, in the conventional apparatuses such as that shown in FIGS. 60 and 61, there are the following defects (1) to (3):
FIG. 62 shows another example of the screen fitting. In this example, one lenticular lens and a plurality of Fresnel lenses form an integral screen of a multipicture by using a fitting frame.
In FIG. 62, the reference numeral 20 represents a front surface part unit of a multiscreen display. In this front surface part unit 20, a screen 30 is fitted by a screen fitting frame 21.
In this screen, four upper, lower, left and right regions 31, 32, 33 and 34 are set, and image lights are projected from the four respective projecting units.
FIG. 63 is a sectioned view of the front surface part unit 20 in FIG. 62.
As shown in FIG. 63, in the screen 30 shown in FIG. 62, Fresnel lenses 37 are arranged in the four upper, lower, left and right regions 31, 32, 33 and 34 between the thickest transparent plate (such as, for example, an acrylic plate) 35 and the thinnest lenticular lens 36.
The Fresnel lenses 37 weaken the diffusion of the image lights from the respective plurality of the projecting units and lead them to the lenticular lens 36. The lenticular lens 36 forms a vertically striped lens on the front surface side of a semitransparent plate, images the image lights from the Fresnel lenses 37, and further diffuses them to the right and left. A black painting 38 is applied to the periphery of the Fresnel lens 37 to prevent the adjacent projecting units from interfering with lights.
FIG. 64 is an explanatory view for explaining to prevent the projecting units from interfering with image lights.
In FIG. 64, as lights are absorbed by the black painting 38 between the Fresnel lenses 37. When the projection of the image lights between the upper and lower (or right and left) projecting units is small, no interference with the image lights by different projecting units will occur because the black paint on the Fresnel lens border will stop such interference. However, because the transparent plate 35 is formed of one plate having no interior border upon which black paint may be placed, as shown by the solid lines B31 and B32, when the lag of the image lights from the projecting units is large, the image lights will cross the black painting 38 and an interference will occur. Therefore, the boundary line of the projected image will have to be controlled by controlling the luster size of the projecting unit and it will be a very difficult control in some signals having different frequency characteristics.
When the Fresnel lenses 37 are forcibly fixed to the transparent plate 35 with nails, the ratio of the expansion and contraction and the progressing velocity will be changed by the difference in plate thickness between the transparent plate 35 and the Fresnel lenses 37. As a result, a strain will be produced between the transparent plate 35 and the Fresnel lenses 37. Therefore this screen is useful only where little temperature variation is experienced, such as a room. In addition, as the four Fresnel lenses 37 are fixed into one, moving, conveying and installing is difficult. Further, as the transparent plate 35 and screen fitting frame 81 must have sufficient strength, they are heavy and the handlability will be lower.